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Finding the Fourth Proportional to 687.20, 948.36 and 392.55

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Solution

The fourth proportional to 687.20, 948.36 and 392.55 is: 541.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.20 : 948.36 = 392.55 : x
  2. Step 2: Convert to fraction form
    687.20/948.36 = 392.55/x
  3. Step 3: Cross multiply
    687.20x = 948.36 × 392.55
  4. Step 4: Simplify right side
    687.20x = 372,278.72
  5. Step 5: Solve for x
    x = 372,278.72/687.20
  6. Step 6: Final answer
    x = 541.73

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.